1. Field of the Invention
This invention relates to a vehicle mounted machine for cutting and removing a plug of turf to create a new putting cup hole in a golf putting green and, if desired, for moving the newly cut turf plug to an old cup hole and inserting it therein to close it.
2. Description of the Prior Art
In order to prevent undue wear and deterioration of golf course putting greens around the putting cup, it is generally accepted practice to change the location of the cup on each playing green and on the practice greens frequently, preferably once each day. At present, a manual plug cutter, comprising a handle with a hollow cylindrical cutter at the end thereof, is used to cut putting cup holes. The cutter is pressed downward and twisted into the turf to a depth of eight inches to cut a turf plug having an outside diameter equal to the diameter of the putting cup. The cutter is lifted from the earth with the plug therein which is used to fill the old cup hole. The dept of penetration of the cutter is always the same, as the new plug should be of a length sufficient to exactly fill the old hole with the top thereof exactly flush with the surrounding surface of the green. In practice, it is very difficult to always obtain a turf plug of consistent length because some of the soil breaks free from the end of the turf plug and falls away when the plug is removed from the ground. Thus, the turf plug is usually too short and it must be trial fitted into the old hole. If it is too short it must be removed to permit a mixture of sand and soil to be added to the bottom of the old cup hole. When the fitting is completed, the turf plug is inserted and tamped down. This fitting of the turf plug is an exacting procedure that takes time and the turf plug is frequently improperly fitted into the old hole. Examination of any putting green will show a plurality of slight depressions each caused by a turf plug that was not long enough and which subsided after repeated watering of the green and also scalped areas where the turf plug was a little too long causing the top of the plug to be slightly above the surrounding surface and thus scalped by the mower during grass cutting.
One reason that soil breaks free from the manually cut turf plug is that the root system of the turf that holds the soil within the plug is broken as the plug is being cut. The roots will grow down as far as fourteen inches and this network of roots, if unbroken, will hold the soil in the plug together. Also it is very important to retain this root system in a turf plug intact as the root system provides the strength for new grass growth when the plug is transplanted. When the cutter is inserted into the ground, the soil will adhere to the inside of the cutter and this adhesion is why the turf plug will remain in the cutter when it is pulled from the ground after the plug has been cut. However, this adhesion also causes root breakage during manual cutting of the turf plug. In cutting the cup hole manually, the cylindrical cutter is usually twisted about 180.degree. and then stopped as the operator must alternate his grip on the handle or the cutter is twisted back and forth with the cutter stopping each time the direction of cutter rotation changes. As discussed above, when the cutter stops, the soil and turf of the plug adheres to the inside of the cutter and when rotation of the cutter is started again, the plug will tend to rotate with the cutter resulting in a shearing action at the interface where the soil within the cutter meets the stationary soil in the ground below the cutter. This shearing breaks the roots. Root breakage can occur quite close to the surface. This shearing action is accentuated by wobbling the cutter handle which causes the plug to be tilted and, in addition, wobbling can cause the hole to be larger than the cup insert. Ideally, the plug when cut should comprise one continuous, unbroken turf cylinder with the network of roots intact to hold all the soil so the plug is always the same length. In actual practice, it is not at all unusual for the shearing action to take place several times as the cutter is started and stopped, sometimes resulting in the soil fracturing to the degree that much of the soil may fall out as the cutter is removed thus making a mess on the green and making depth control even more difficult. More importantly, the destruction or shortening of the root system in the turf weakens the grass and can result in dead or sickly spots on the green.
The changing of putting cup hole locations if done right can take as much as three hours of the green-keeper's time each day and therefore is expensive. In spite of the time involved to change putting cup locations and the unreliable results of hand plugging of the old hole, there has not been a commercially successful mechanical putting cup hole cutting machine developed for mounting on a power driven vehicle that meets desired requirements.
More specifically, some of the requirements that a mechanical putting cup hole cutting machine should meet are as follows. The machine should permit the vehicle to be located in the general area where the cup hole is to be dug, and while the machine is stationary, permit the cutter to be accurately repositioned independently of the vehicle in both fore, aft and lateral directions to a precise hole location. It is also desirable that the vertical axis of the cutter be adjustable to assure that the cup hole axis will be vertical so the "pin" or flag staff will stand straight up in the cup. The ability to precisely locate the putting cup is necessary for various reasons. For example, golf tournament committees designate different exact locations for the pin each day of the tournament. Also when the new turf plug has been cut, it is necessary that the vehicle be repositionable to the general area of the old hole and the cutter then accurately repositioned independently of the vehicle so that the cutter can be accurately aligned to insert the turf plug into the old cup hole.
In addition, the machine should have provision to permit the turf plug to be retained or not retained in the cutter. For example, when cutting a new cup hole, the plug should be allowed to remain within the cutter as the cutter is withdrawn from the ground. This permits the cutter with the turf plug therein to be moved to and inserted in the old cup hole. By being able to accurately reposition the cutter, the turf plug can be retained in the cutter and manual handling of the plug avoided. This will minimize root system breakage and maintain precise turf plug length to minimize leveling and subsidence problems. After inserting the plug in the old cup hole, the cutter must be withdrawn and while doing so it is necessary that a means be provided to hold the turf plug in the ground as the cutter is withdrawn.
The machine should be compact and light in weight so that it can be mounted on a vehicle such as a tractor mounted mower for cutting the greens and retained thereon even when the tractor is in use to cut the grass on putting greens. This will permit the cup location to be changed at the same time the green is cut to save time. The machine should also permit easy attachment on and detachment from the tractor and be powered preferably by hydraulic actuators so as to be able to use the existing hydraulic system of the tractor.
The cutter per se will be subject to wear and dulling of the cutting edge and the service of a cutter at or near the ground is difficult and time consuming. Thus, it is preferable that the machine has provision to permit the cutter to be easily and quickly orientated to and locked in a special service position convenient for cutter removal or sharpening.
U.S. Pat. No. 3,817,337, issued June 18, 1974 to Philip F. Panak and Elwin J. Bronson, discloses a machine for making holes in putting greens. This machine makes no provision for adjusting the fore and aft, lateral and vertical alignment of the cutter relative to the vehicle. Further, this machine first forces the cutter down into the turf without cutter rotation until downward action is resisted, at which time rotation of the cutter is started. This is an undesirable procedure because on many occasions the plug of turf in the cutter will rotate with the cutter and break off the root system.
There are also prior patents relating to soil sampling machines which either use augers or force a core cutting tube cutter into the ground. U.S. Pat. Nos. 3,057,415, issued Oct. 9, 1962 to P. D. Cox, and 3,324,958, issued June 13, 1967 to R. A. Clark, are typical of such machines. These soil sampling machines have no provision for ultra-precise relocation of the cutter position after the vehicle is in a stationary position. U.S. Pat. No. 3,224,512, issued Dec. 21, 1965 to J. P. Alexander, discloses a typical soil sampler having a cutter that can be tilted about a single horizontal axis but there is no provision permitting fore and aft or lateral adjustment of the cutter.
It is also known from prior art hole drilling machines, such as shown in U.S. Pat. No. 3,017,935 issued Jan. 23, 1962 to S. W. Bilbraith et al, to mount an auger and its rotary drive motor on the end of an elevatable and laterally swingable boom by means of a gimbal but there is no adjustment of the auger fore and aft of the boom to provide ultra-precise location of the auger.